1. Field of the Invention
This invention relates to a pneumatic tire capable of controlling complicated movements of the tire or the so-called wandering phenomenon not predicted by a driver. This is produced when the tire is run at a higher speed on a road surface having slant portions or a rutted road surface, to improve a straight running stability.
2. Description of the Related Art
The high performance tire of this type is required to have a large lateral rigidity against a large lateral force produced in the tire during cornering or the like and excellent traction and braking performances in the high-speed running, steering stability and so on with a high power of a vehicle. For this end, tires having a wider ground contact width by making an aspect ratio small have become popular.
The tire having a small aspect ratio exhibits an excellent steering stability on a flat road surface. However, when the aspect ratio is particularly not more than 60%, if the tire having such an aspect ratio is run at a higher speed on a road surface having slant portions such as a rutted road surface or the like, a non-uniform force is locally applied to the tire due to the disorder of the road surface to produce complicated movements of the tire or the so-called wandering phenomenon, whereby the vehicle is moved in a direction not predicted by a driver. Such a wandering phenomenon is a risky factor damaging the straight running property of the vehicle, which becomes in a serious problem with the advance of high running performances of the tire.